Teiid runtime versions prior to 9.0 do not support a VDB version that is not an integer.
Since your runtime is 8.12.5, using any version other than a simple integer will fail deployment. So changing it to an integer would allow deployment.
We did have the logic to check the version number, but there is an error in the code preventing proper handling of that warning. I've logged an issue to fix the problem and warn the user if this version situation exists.